Question

What is differential protection of alternator?

Answer 1

Differential protection of alternator or Merz-Price circulating current protection system is a only protection system that protects alternator stator from burning through at least 80% of it.

For alternator the most severe out come of fault is the damage of stator. If some how the stator coil is burn out, welded together then there is no solution but to replace it causing longer down time. Other faults of alternator like reverse power, stator inter turn, excitation circuit protection are either rare or can be detected easily. The core concept of alternator stator protection is to save 85% of its coil from damage due to fault.